itc.pidi-3-docs/figures/code/zip-archive.cs

/// <summary>
/// Streams the prepared documents into a ZIP archive written directly onto <paramref name="destination"/>
/// </summary>
public async Task WriteZipArchiveAsync(
    OrgSlug orgSlug, IEnumerable<DocumentRelativePath> documents,
    Stream destination, CancellationToken cancellationToken)
{
    await using var zip = await ZipArchive.CreateAsync(
        destination, ZipArchiveMode.Create, leaveOpen: true,
        entryNameEncoding: null, cancellationToken);

    foreach (var path in documents)
    {
        var key = new DocumentKey(orgSlug, path.Type, path.Name);

        using var response = await TryGetObjectAsync(new GetObjectRequest
        {
            BucketName = _settings.S3.Bucket,
            Key = key.ToString(),
        }, cancellationToken);

        if (response is null)
            continue;

        var entry = zip.CreateEntry(path.ToString(), CompressionLevel.Optimal);
        await using var entryStream = await entry.OpenAsync(cancellationToken);
        await response.ResponseStream.CopyToAsync(entryStream, cancellationToken);
    }
}

private async Task<GetObjectResponse?> TryGetObjectAsync(GetObjectRequest request, CancellationToken cancellationToken)
{
    try
    {
        return await s3.GetObjectAsync(request, cancellationToken);
    }
    catch (AmazonS3Exception exception) when (exception.StatusCode == HttpStatusCode.NotFound)
    {
        return null;
    }
}